Field of the Invention
The present invention generally concerns handling of embryos. More particularly, the present invention relates to an apparatus and process for performing in vitro fertilization (IVF) and washing techniques.
Related Art
Technology-assisted reproduction techniques in which embryos are handled independently from their mammalian biological source are growing in importance and frequency of use. Such techniques have great direct benefit to persons unable to have babies through unassisted sexual reproduction. In some instances, such assisted reproduction techniques are employed to control faster genetic evolution of a mammal, such as cattle or fish, and permitting the genetic characteristics of the single exceptional mammal to be passed on to far greater numbers of offspring than would be possible through unassisted sexual reproduction.
Embryo manipulation is becoming more routine due to the development of gene manipulation, cloning, and in vitro fertilization (IVF) techniques. The overall goal of embryo manipulation may be to increase production efficiency, especially with regard to reproduction, milk production or production of specific milk components, lean tissue growth with reduced fat content and decreased susceptibility to specific diseases. Embryo transfer is also used to introduce or rescue valuable germplasm and to propagate rare breeding animals such as endangered exotic species.
Expense and relatively low success rates place significant burdens on the use of these assisted reproduction techniques for humans as well as other mammals. In human reproduction, such expense and failure may add emotional as well as economic burdens. In addition, safeguards against failures often result in unwanted or unmanageable multiple births, as well as additional stored embryos which may require maintenance and additional difficult decision making at some later point in time. Expense is generally a primary concern, for example, in animal reproduction.
Failure rates in reproduction techniques as well as testing and other embryo handling techniques are attributable primarily to the significant handling and manipulation of embryos in executing these techniques. Animal reproductive technologies have advanced in recent years, but the physical tools used in animal reproduction have not changed significantly. Fine-bore glass pipettes are still one of the basic tools of the embryologist. Using standard petri dishes, procedures such as in vitro maturation of eggs (IVM), in vitro fertilization (IVF) and embryo culture (EC) require picking up and placing individual eggs and embryos several times for each procedure.
Such handling and movement from one petri dish to another provides significant potential for damage or contamination. Perhaps more important, though, is the failure of a stationary embryo in a petri dish to simulate the corresponding natural biological reproduction condition. Some efforts have been made to move embryos in petri dishes via agitation of the dish, but this is a haphazard approach. Expense is also created here due to the relatively large amount of biological medium required for the manual petri dish conventional embryo handling methods. Bovine embryos are individually handled with pipettes and large, expensive manipulators. Large quantities of biological medium, including growth agents for human embryo culturing, renders the corresponding in vitro procedure even more expensive.
Such static culture systems also fail to allow for changing the milieu in the culture medium as the embryo develops. Current culture systems with flowing medium have limited volumetric culture chambers. However, a concern exists if the culture volumes are greater than needed and medium is replenished too quickly. The endogenous growth factors that enhance development may be diluted out and washed away.
Furthermore, a concern also exists during manual techniques for washing embryos to reduce rates of pathogen transmissions employed in washing steps (e.g., typical washing steps may include ten washes per embryo). Typical prior-art systems require a laborer to manually monitor and manipulate embryos from one media to another during washing procedures. This method is not only labor and time intensive, but, may also subject the embryos to contaminants during treatment. In addition, once IVF and washing techniques are complete, it may be further necessary to treat the embryos in another remote facility. Conventional systems require the embryos to be manually placed in shipping containers for transport. Again, this potentially places the embryos at risk by exposing them to contaminants or other risks during passage. The same is true when the embryos arrive at the remote location and need to be handled for further treatment and/or manipulation.
Thus, there is a need for an improved embryo handling device and method which addresses problems in known embryo handling techniques. An improved embryo handling device and method should provide for an improved simulation of natural conditions. It should also provide a building block upon which larger and/or more powerful and accurate instruments may be based, such as embryo culturing systems, embryo analysis systems, embryo storage systems and similar systems.